/*
 * Copyright 1999-2011 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.druid.sql.dialect.odps.parser;

import com.alibaba.druid.sql.ast.SQLExpr;
import com.alibaba.druid.sql.ast.expr.SQLCharExpr;
import com.alibaba.druid.sql.parser.Lexer;
import com.alibaba.druid.sql.parser.SQLExprParser;

public class OdpsExprParser extends SQLExprParser {

    public final static String[] AGGREGATE_FUNCTIONS = { "AVG", //
            "COUNT", //
            "LAG",
            "LEAD",
            "MAX", //
            "MIN", //
            "STDDEV", //
            "SUM", //
            "ROW_NUMBER"//
                                                     };

    public OdpsExprParser(Lexer lexer){
        super(lexer);

        this.aggregateFunctions = AGGREGATE_FUNCTIONS;
    }

    public OdpsExprParser(String sql){
        this(new OdpsLexer(sql));
        this.lexer.nextToken();
    }
    
    protected SQLExpr parseAliasExpr(String alias) {
        return new SQLCharExpr(alias);
    }
}
